A union representing Lufthansa's pilots is threatening a new round of strikes in a long-running dispute over wages and early retirement benefits.

The Vereinigung Cockpit union says in a statement it may order pilots to strike "starting immediately" because negotiations have failed to achieve their goals. The union didspn't specify when this might happen but said it would give advance warning.

Lufthansa, Germany's biggest airline, called the union's position incomprehensible.

A three-day pilots' strike in April grounded Lufthansa and its Germanwings and Lufthansa Cargo subsidiaries.

The pilots want Lufthansa to keep paying a "transition" benefit for those who retire early, while the airline wants to cut those extra payments. The pilots also seek a salary increase of 10 percent.

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